The field of the invention is motor vehicle parts and the invention relates more particularly to mufflers for motor vehicles.
Muffler designs of many configurations exist in the prior art. Some mufflers which contain conical sound deadening members include U.S. Pat. Nos. 1,922,848; 1,953,264; 2,185,584; 2,933,148; 4,325,459 and 4,979,587.
Automobile enthusiasts like to have the ability to modify their muffler so that it matches their vehicle and the type of driving which they intend to do. For some types of driving, they wish to have degree of muffling and for others, a low degree. They also like to be able to vary the back pressure to optimize the performance of their vehicle.